U.S. patent number 4,181,365 [Application Number 05/784,053] was granted by the patent office on 1980-01-01 for wheels for motorcycles.
This patent grant is currently assigned to Honda Giken Kogyo Kabushiki Kaisha. Invention is credited to Takeshi Kawaguchi, Yasuhisa Kobayashi, Masayuki Onimaru.
United States Patent |
4,181,365 |
Kawaguchi , et al. |
January 1, 1980 |
Wheels for motorcycles
Abstract
A spokeless wheel for a motorcycle or other vehicle is made by
combining a wheel hub with a wheel rim through several sets of
plates, wherein each set includes two opposed plates. In the
vertical cross-section, the plates form an isosceles triangle with
the hub forming the base of the triangle.
Inventors: |
Kawaguchi; Takeshi (Fujimi,
JP), Kobayashi; Yasuhisa (Saitama, JP),
Onimaru; Masayuki (Kawagoe, JP) |
Assignee: |
Honda Giken Kogyo Kabushiki
Kaisha (Tokyo, JP)
|
Family
ID: |
27461372 |
Appl.
No.: |
05/784,053 |
Filed: |
April 4, 1977 |
Foreign Application Priority Data
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Apr 8, 1976 [JP] |
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51-43487[U] |
May 1, 1976 [JP] |
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51-55235[U]JPX |
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Current U.S.
Class: |
301/67;
301/64.202; 301/74; 301/75; 301/95.104 |
Current CPC
Class: |
B60B
1/10 (20130101); B60B 1/14 (20130101) |
Current International
Class: |
B60B
1/04 (20060101); B60B 1/00 (20060101); B60B
001/10 (); B60B 001/14 () |
Field of
Search: |
;301/6V,63DD,63DS,64R,64SH,67,73,74,79-80,78,75,62,72,66 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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430565 |
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Aug 1911 |
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FR |
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683521 |
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Mar 1930 |
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FR |
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512 of |
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1894 |
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GB |
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6201 of |
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1896 |
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GB |
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11217 of |
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1891 |
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GB |
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113179 |
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Feb 1918 |
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GB |
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Primary Examiner: Marmor; Charles A.
Attorney, Agent or Firm: Weiner; Irving M. Burt; Pamela S.
Yedlin; Melvin
Claims
We claim:
1. A wheel for a vehicle, comprising:
a wheel hub;
a wheel rim having at least one projection on its inner
surface;
a plurality of pairs of plates which are mechanically and operably
connected to said wheel hub and said rim projection;
said wheel hub, said rim projection and each of said pairs of
plates forming in a vertical cross-section a triangle having said
rim projection at the apex of said triangle, the base of said
triangle being formed by a portion of said wheel hub;
each plate of said pairs of plates having fitting parts provided at
spaced-apart edge portions on the end of said plate connected to
said wheel hub; and
said fitting parts being overlapped on the fitting parts of
adjacent plates on both sides of each said plate, and firmly
connected thereto.
2. A wheel according to claim 1, wherein:
holes are respectively provided in said fitting parts on the hub
end of each said plate of said pairs of plates; and
said overlapped fitting parts are rigidly connected by a fastening
member provided through said holes.
3. A wheel according to claim 2, wherein:
said fitting parts expand sidewise from both spaced-apart edge
portions of each said plate of said pairs of plates, on the end
thereof connected to said wheel hub.
4. A wheel according to claim 3, wherein:
one of said fitting parts on the hub side is made to project in the
direction of the wheel axle to form a stepped part and the other of
said fitting parts is made to be flat.
5. A wheel according to claim 1, including:
said rim projection is formed to be wide on the outer peripheral
side and narrow on the inner peripheral side so as to be in the
form of a trapezoid in cross-section; and
a fitting part on the rim side of said each plate is bent outwardly
to be in conformity with each tapered side surfaces of said rim
projection.
6. A wheel according to claim 5, including:
a tip of said fitting part on said rim side is bent outwardly to be
in contact with the inside surface of said rim.
7. A wheel according to claim 1, wherein:
each said plate of said pairs of plates is provided at each end in
the lengthwise direction thereof which extends between said hub and
said rim with two fitting holes separated from each other in the
width direction of each said plate, and is connected to said wheel
hub and said rim projection by inserting shaft-shaped fastening
members, through said fitting holes; and
one of said fitting holes in each said plate of said pairs of of
plates is made to be a positioning hole to tightly fit said
fastening members and the other holes are made to be holes loosely
fitting said fastening members.
8. A wheel according to claim 7, wherein:
one of the fitting holes in the hub end of each said plate of said
pairs of plates is made said positioning hole.
9. A wheel according to claim 7, wherein:
the center line of each said plate of said pairs of plates in the
vertical cross-section is intersected at the intersection of the
axis of said fastening member with the side surface of said rim
projection on which side each said plate is disposed.
10. A wheel according to claim 9, wherein:
an end part of each said plate of said pairs of plates, having
fitting holes to be connected to said rim projection, is pressed
out toward said rim projection so as to be in conformity
therewith.
11. A wheel according to claim 5, wherein:
said fitting part on the rim side of each said plate of said pairs
of plates is connected to said tapered surface of said rim
projection through fastening members by providing a washer having a
tapered surface so that a fitting seat surface vertical to the
wheel axel is provided.
12. A wheel according to claim 11, wherein:
said washer is provided on said fitting part of each said plates of
said pairs of plates; and
each said plate of said pairs of plates contacts said rim
projection directly.
13. A wheel according to claim 11, wherein:
said washer is provided on said tapered surface of said rim
projection; and
each said plate of said pairs of plates is overlapped and fastened
from outside on said washer.
14. A wheel according to claim 2, wherein:
an exposed outside surface of said fastening member is protected
with a cover.
15. A wheel according to claim 2, wherein:
each said plate of said pairs of plates is provided at both sides
with flanges bent inwardly.
Description
This invention relates to wheels for vehicles.
More particularly, the invention relates to a wheel to be used
primarily for autobicycles or motorcycles wherein a wheel rim and
hub are combined with each other through a plurality of sets of two
plates each divided in the direction of an axle instead of spokes,
so that the wheel may be simplified in structure and assembly,
improved in appearance, and reduced in cost while remaining strong
and rigid.
BACKGROUND OF THE INVENTION
Heretofore, wheels used for motorcycles have been generally of a
type wherein a rim and hub are combined with each other through
spokes.
Such spoke type wheel require so many spokes that the number of
component parts including fitting members to the rim and hub of
each wheel, is great. The number of steps of assembling spokes is
great and the assembling requires many manual operations, many
workers, and much time. Further, the workers must be skilled.
Because the spokes are to support the rim and hub with the tension
and compression of wire materials, each spoke is required to be
assembled with a substantially uniform fastening force and is
difficult to assemble and balance. Therefore, there are so many
steps in manufacturing such wheels that it is difficult to save
labor, the number of component parts is so great that the wheel is
costly, and there are problems in reducing the cost of the wheel or
of the motorcycle.
In the spoke type wheel, because the spokes are fastened and
combined, they will become loose, and thus special tools are
required to tighten them. It is necessary to tighten them by
considering the balance of the whole, and great skill is required
for such tightening work.
A disk type wheel has been used wherein, as in an automobile,
spokes are eliminated. The rim and hub are combined with each other
through a disk, or the rim and disk are made integral with each
other and are combined with the hub, but this also results in many
problems.
When used as a wheel for motorcycles, this type of wheel is exposed
on both surfaces and the disk may not have a good appearance, will
appear to be dull, will be heavy, and will result in various
problems if the disk is used, the weight of the wheel will be high.
In case the wheel is used for a front wheel or the like, the
steering will not be light. In view of the above, a disk could be
punched to reduce the weight and to improve the appearance.
However, as the disk is punched and cut, the material will be
wasted. This will not be desirable in saving the material
resources. Particularly, on a motorcycle, the wheel is so important
to the appearance and design of the entire vehicle that it is
necessary to use a material good in appearance and high in cost and
treated on the surface by plating.
SUMMARY OF THE INVENTION
The present invention provides a wheel for a vehicle, which wheel
includes a wheel hub, and a wheel rim having a projection on its
inner surface. At least one set of plates mechanically and operably
connects the wheel hub to the rim projection. The plates, the wheel
hub and the rim projection form in a vertical cross-section
triangle having the rim projection at the apex of the triangle, and
the base of the triangle being formed by at least a portion of the
wheel hub.
An object of the invention is to provide a wheel for a vehicle
wherein a rim and hub are combined with each other through plates
so as to be a spokeless wheel, and so that the various problems of
spoke type wheels and disk type wheels are avoided.
An object of the invention is to provide a practically excellent
wheel which is simpler in structure and assembly and much lower in
the number of component parts than a spoke type wheel, is easy to
produce, is much better in appearance and design than a disk type
wheel, is effective to save material, can be made high in strength
without impairing appearance, and can be inexpensively
manufactured.
Particularly, an object of the invention is to provide a wheel
wherein a projection is provided on the inside diameter portion of
a wheel rim, and two plates in each set are joined with each other,
opposite to each other, on opposite surfaces; of the above
mentioned projection, and on both surfaces of a hub so as to
combine the rim and hub with each other. A plurality of sets of two
plates each are arranged on the periphery, and the plates of each
set are made to have a small fitting distance on the rim side, but
large on the hub side. The plates are combined to form an isosceles
triangle in their vertical cross-section in the direction of the
axle, with the apex on the rim side and the base on the hub
side.
An object of the invention is to provide a wheel which is
spokeless, and made by combining a rim and hub with each other by a
plurality of sets of two plates each opposed to each other to form
an isosceles triangle in their vertical cross-section in the
direction of the axle, with the apex on the rim side and the base
on the hub side, forming a wheel which is stronger in vertical
rigidity, vertical load strength, horizontal rigidity, and
horizontal load strength than a disk type wheel.
A further object is to provide a wheel including a rim wherein a
projection is provided in the form of a ring over the entire
periphery of the inside diameter portion and is adapted to be used
as a plate fitting member so as to increase the strength and
rigidity of the rim, while making the rim lighter.
A further object is to provide a wheel including a structure for
combining plates with a projection of the inside diameter portion
of a rim wherein plates are combined with tapers on both sides of a
projection formed by extruding and shaping the inside diameter
portion of a rim by inserting and providing tapered washers between
each plate and the projection so that axes of such combining
members as rivets may conform to the axis of the wheel to make the
combination of the plates strong and positive.
A further object is to provide a wheel including a combining
structure wherein plates are formed at the fitting ends, so that
the center line of each plate is intersected at the intersection of
the combining member with each side surface of the projection, to
support the load in the lateral direction acting on the projection
of the inside diameter portion of the rim and to improve the
rigidity and strength of the joint between the projecton of the
inside diameter portion of the rim and the plate.
An object is to provide a wheel including a combining structure
wherein both sides of a projection of the inside diameter portion
of a rim are tapered. The joining part of a plate to the side of
the projection is bent to conform with the tapered surface to be
joined with it. When the plate and projection are combined with
each other through rivets, this reduces the shearing stress and
prevents stress concentration in the rivet, and improves the
rigidity and strength of the combining part so that the opening
angle between the plates of a set of two plates may be made
small.
A further object is to provide a wheel wherein combining members
for plates with a projection of the inside diameter portion of a
rim are covered with a cover to protect and shield the combining
part, and to improve the appearance and design.
A further object is to provide a wheel including a combining
structure wherein a part a plate which joins with a projection of
the inside diameter portion of a rim is bent outwardly at tne end.
The bent part is contacted with the inside diameter portion of the
rim on each side of the projection to improve rigidity and strength
of the wheel in the vertical and peripheral directions.
A further object is to provide a wheel including a structure for
combining plates wherein combining parts at both ends of a fitting
part of a plate to a hub are formed to overlap those of the
adjacent plate, so that they may be combined through a single
combining member, such a bolt, to allow increasing the span of the
members combining the plate with the hub, to improve rigidity and
strength of the combining part, to reduce the number of component
parts, to reduce the combining steps, and to improve the ease of
assembly.
Another object is to provide a wheel including plates wherein a
groove or rib is provided in the lengthwise direction of each plate
to improve the strength and rigidity of the plate. A through hole
with the peripheral part raised is made in the lengthwise direction
of the plate to increase the strength and rigidity of the plate and
allow the forming of a bend in the width direction of the plate to
improve the appearance and design.
An object is to provide a wheel including a structure wherein one
of the fitting holes made in an end portion of each plate is
arranged as a positioning hole with precision. The other holes are
formed as loose holes for the combining members to efficiently
allow a precise plate assembling step, and to simplify the
manufacture of the wheel.
A primary object is to provide a wheel formed by combining a rim
and hub with each other through a plurality of sets of two plates
each to define an isosceles triangle with the apex on the rim side
and the base on the hub side in the vertical cross-section in the
direction of the axle.
The cross-sectional area of the plate, opening angle between the
plates, number of sets of plates, length of the plate, and
thickness of the plate material are so selected that the rigidity
coefficient of the plate may be greater than a specific range. The
thickness of a projection on the inner diameter portion of the rim
is made to be in a specific range so as to make the combination of
the rim and hub through the plates so strong as not to be loosened
by vibrations or the like while running. With respect to the
steering stability of a motorcycle, in the convergence of external
disturbances, such as vibrations, received by the wheel from a road
surface, the rim and hub are combined through the plate to subject
one of the plates of the set to tension, and the other plate to
compression to retain the strength and rigidity of the wheel while
providing the steering characteristics of a spoke type wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view schematically showing a wheel according to a
first embodiment of the invention.
FIG. 2 is a vertically sectioned view in the axial direction of the
FIG. 1 wheel, only a half of the wheel being magnified.
FIG. 3 is a view seen in the direction indicated by arrow 3 in FIG.
2, showing only essential parts.
FIG. 4 is a disassembled perspective view schematically showing
another embodiment combining the tip part of a plate with a
projection on the inside diameter portion of a rim through a
washer.
FIG. 5 is a sectioned end view showing the FIG. 4 combination.
FIG. 6 is a view of a modification of FIG. 5.
FIG. 7 is a sectioned view of a combining part for explaining a
problem in the case of combining a plate with a projection of the
inside diameter portion of a rim by rivets or the like.
FIG. 8 is a perspective view of an improved fitting part of a plate
for the FIG. 7 projection.
FIG. 9 is an explanatory sectioned view showing the FIG. 8 improved
fitting structure.
FIG. 10 is an explanatory view of a combining structure made to
reduce the shearing stress and to prevent stress concentration in
the rivet.
FIG. 11 is a sectioned view of a combining part for explaining
another problem in the combination of a plate with a projection of
the inside diameter portion of a rim.
FIG. 12 is a view similar to FIG. 11, showing an improvement
according to the invention.
FIG. 13 is a cross-sectional view of a plate.
FIG. 14 is a cross-sectional view showing another embodiment of a
plate.
FIG. 15 is a cross-sectional view showing another embodiment of a
plate.
FIG. 16 is a cross-sectional view showing still another embodiment
of the same.
FIG. 17 is an explanatory view to show a fitting structure of a
plate.
FIG. 18 is an explanatory view showing a regulation at the time of
fitting the FIG. 17 plate.
FIG. 19 is a disassembled perspective view of a plate, showing a
fitting structure in which the fitting part of a plate to a hub is
improved.
FIG. 20 is a magnified sectioned view on line 20--20 in FIG.
19.
FIG. 21 is a magnified sectioned view on line 21--21 in FIG.
19.
FIG. 22 is an explanatory view of a combination of a rim and hub
through an improved fitting structure.
FIG. 23 is a schematic sectioned view on line 23--23 in FIG.
22.
FIG. 24 is a schematic explanatory view shown to explain the
setting of preferable conditions of a wheel according to the
invention.
FIG. 25 is a graph showing a convergence of a steering angle of a
steering handle of a motorcycle.
FIG. 26 is a graph showing relative characteristics of rigidity and
attenuation rate.
DETAILED DESCRIPTION
FIGS. 1 to 3 show a fundamental structure of a wheel according to
the invention.
A wheel 100 comprises a rim 30, two plates 70, and a hub 50.
Rim 30 is shaped by extruding or rolling an aluminum alloy or the
like, and is formed to be ring-shaped. Rim 30 is provided with a
substantially flat body 31 parallel with the axis of an axle, and
ear pieces 32 erected on the outer periphery on the right and left,
respectively, of body 31 integrally shaped to be ring-shaped.
Spaces 33 (FIG. 2) are provided on the right and left over the
entire periphery within body 31 to make body 31 thick and light,
yet improved in strength.
A projection 35 of a small width projects from the inside diameter
of the rim 30 in the central part in the width direction, i.e.,
toward the center of the wheel, and centered on rim 30. Projection
35 is integral with body 31. A number of such projections 35 may be
provided in inside diameter portion 34 of the rim. But preferably,
projection 35 is provided to be ring-shaped over the entire
periphery of portion 34. Projection 35 provided over the entire
periphery acts as a rib to improve the strength in the inside
diameter portion, and improves the rigidity and strength in the
vertical direction of rim 30. A part of projection 35 is cut at 36
to accommodate an air valve 102 of a tire.
Each set is formed of two plates 70. Plates 70 are symmetrical. A
plurality of such sets are prepared. Plate 70 is a press-shaped
product of a steel plate material. Because the wheel is exposed on
an autobicycle or motorcycle, in consideration of anticorrosion and
appearance, it is preferred that the plate be of a stainless steel
plate material of a good appearance, or a steel plate material
treated on the surface by plating.
Plate 70 shown in FIGS. 1 to 3 is shaped as shown in FIG. 13. The
plate is formed to be wide in its base part 71 on the hub fitting
side, and to be narrow in its tip part 72 on the rim fitting side.
In the illustrated embodiment, plate 70 is curved to be wider at
base part 71, is linearly tapered toward tip part 72 from the
curved base part, and is formed to be somewhat wider in part 72 so
as to be a fitting part. The inner peripheral edge 73 of part 71 is
formed to be arcuated with the same curvature as the outer
peripheral surface of the arcuated stepped part 52 of the
intermediate portion of hub 50. The outer peripheral edge 74 of
part 72 is arcuated with the same curvature as to the inner
peripheral surface of portion 34 of rim 30.
In FIGS. 1 to 3, plate 70 has a through hole 75 formed in the
lengthwise direction in the intermediate portion in the width
direction to lighten it. As shown in FIG. 13, a rib 76 is formed by
raising the peripheral edge part of the entire inner periphery of
hole 75 toward the back surface. Both edge parts 77 of plate 70 are
also bent toward the back surface side to increase rigidity and
strength of the plate and to improve the design, together with rib
76.
The cross-sectional shape of plate 70 can be selected from the
various embodiments shown in FIGS. 14 to 16.
In FIG. 14, a concave groove 175 is formed in the intermediate
portion of a plate 170, and both edge portions of the plate are
curved toward the back surface. In FIG. 15, a plate 270 is V-shaped
in cross-section, and is provided with an edge 275 passing radially
through the intermediate portion. In FIG. 16, a flat plate 370 is
provided with a semicircular rib 375 on the front surface in the
central portion.
The cross-sectional shape of plate 70 is determined by taking the
required vertical and horizontal rigidity and strength of the plate
into consideration.
As shown in FIG. 2, hub 50 has three stepped parts which are
different in width. Hub 50 has the intermediate arcuated stepped
part 52 which is narrower than the body 51, and is wider than an
outer peripheral part 53. An axle inserting hole 54 is made through
the center of body 51. Bearings 55 are fitted in both end portions
within body 51, and a collar 56 is fitted in the intermediate
portion.
Body 51 and the stepped parts 52 and 53 of hub 50 are formed
circular and concentric. Both surfaces 57 of part 53 are
perpendicular to the axis of the wheel, and flat to form seat
surfaces for fitting parts 71 of plates 70.
Plates 70 of each set are symmetrically opposed to each other.
Fitting holes 78 are formed in the parts near both ends of part 71.
An inserting hole 58 is made between both end surfaces 57 through
part 53. A bolt 90 is passed through hole 58 from the hole 78a of
one plate 70a to the hole 78b of the other plate 70b fitted on the
other side. A nut 93 is screwed on bolt 90 to fasten plates 70a and
70b. A groove 91 is made in the end portion of bolt 90, and a dowel
pin 92 is pressed into groove 91 to prevent the nut from
loosening.
Tip parts 72 of plates 70 are contacted with both surfaces of
projection 35. Inserting holes 38 passing through both surfaces 37
are provided in projection 35. Part 72 of each plate is provided
with corresponding fitting holes 79 near both ends. A rivet 94 is
passed through the hole 79a of one plate 70a, the hole 38 of the
projection 35, and the hole 79b of the other plate and is pressed
to bind parts 72 of the plates 70a and 70b to both side surfaces of
projection 35.
Rim 30 and hub 50 are thus combined with each other through the
sets of plates 70. As shown in FIG. 2, in this combined state, the
wheel 100 is narrow at the project 35, but is wide at the hub.
Therefore, plates 70 are bent at 80 and 81. Because each plate is
provided with bends 80 and 81, even if the widths of projection 35
and part 53 are very different from each other, the tip parts 72
and base parts 71 will conform to the fitting surfaces 37 of
projection 35 and the fitting seat surfaces 57 of stepped part
53.
Sets of plates 70 are combined with the rim and hub to be in the
form of an isosceles triangle in which the apex is on projection
35, the base is the outer peripheral portion 59 of the outer
peripheral stepped part 53 of the hub, and the two equal sides
thereof are formed by the plates 70 as shown in FIG. 2. The plates,
five sets in the illustrated embodiment, are radially arranged.
Because the plates 70 in sets are combined to form an isosceles
triangle with the apex on the rim side and the base on the hub
side, a load from a road surface will act on rim 30, plates 70 and
hub 50 through a tire 101 fitted to rim 30. In case a lateral load
F acts on the combining part of the wheel, one plate will be
subjected to a tensile force F.sub.1 but the other plate will be
subjected to a compressive force F.sub.2. The lateral load F will
not act on the plates as a bending force as it would if the plates
were disposed to be parallel. According to the invention,
sufficient lateral rigidity and lateral load strength is obtained,
and an effective wheel of great strength is obtained. Even if the
thickness of the plate is reduced, a sufficient strength is
obtained. Therefore, the plate can be made thin and light. Even if
the plate is simplified in shape and is provided with lightening
slots or holes, lateral rigidity and lateral load strength
sufficient for a wheel is obtained, so that there is freedom to
select the design, and a favorable wheel design can be selected.
Particularly, the wheel for autobicycles is so large in diameter
and so narrow in width as to require high lateral load strength and
lateral rigidity, which can be obtained according to the structure
described above.
Wheel 100 is a front wheel for motorcycles. The rear wheel is the
same, but is somewhat modified in the structure of the hub allow
attachment of a part such as a driving sprocket.
In FIG. 1, the combining part of the plate and rim, i.e., the rivet
combining part is shown as bare. The rivet head is exposed on the
outside of the plate. Therefore, as shown in FIGS. 2 and 3, a cover
103 is fitted to crown and shield the rivet head 95 for a
decorative effect. Cover 103 is a metal or plastic plate which may
indicate a trademark on the surface, and is provided on its back
surface with a holding piece 104 fitting rivet heads 95. Piece 104
is wide enough to crown both rivet heads in the end parts, and is
applied coated with an adhesive in advance to being pressed into
place. Cover 103 is thus secured to rivet heads 95 to shield them
from the elements. Thereby, the combining part is protected and its
appearance is improved.
FIGS. 4 to 6 show a combining structure of parts 72 with projection
35. At the time of extruding and shaping projection 35, the
parallelism of both sutfaces 37 is difficult to maintain, so that
it may be easier to make these surfaces as tapered surfaces.
Projection 35 will be wider in its base part on the inside diameter
of the rim, but narrow on the tip side. When riveting the plate to
the rim, the rivets will be able to distort in comformity with such
tapers due to the plastic deformation of the rivets. But, when
combining them through bolts and nuts instead of rivets, the tapers
are not desirable, since there are no seat surfaces vertical to the
bolt heads and nuts. Therefore, if mechanical work is needed to
maintain the parallelism of both surfaces of projection 35, the
cost will be increased and the number of steps involved in
producing wheels will increase.
In the invention, the problems in combining the plates with the
projection of the inside diameter portion of the rim using bolts
and nuts are solved as follows.
A washer 82 having on its back surface a tapered surface 83
corresponding to the tapered surface on each surface 37 is prepared
for each plate. Washer 82 is provided with holes 84 conforming to
fitting holes 79. The tip parts of plates 70 are contacted with
both surfaces 37. Washers 82 are contacted with the plates from
outside. A bolt 96 is passed through a hole 84 in one washer 82,
the fitting hole 79 in the tip part of plate 70, and the fitting
hole 38 in the projection 35. Another bolt 96 is passed through the
respective holes on the other side, and nuts 97 are screwed to the
bolts 96 to fasten the plates. In this manner, a flat and parallel
seating surface is obtained. This is shown in FIG. 5.
FIG. 6 shows an embodiment wherein the washer is inserted between
the plate and projection. Tapered surfaces 183 on the backs of
washers 182 are in contact with surfaces 37. Fitting seat surfaces
are formed on the outside surfaces of washers 182. The back
surfaces of parts 72 are contacted with the outside surfaces of
washers 182. Bolts 96 are passed through the holes 78, 184 and 38
and are fastened with nuts 97 from the other side. Thus, vertical
fitting seat surfaces can be obtained. The combination by bolts and
nuts has been explained above, but rivets may also be used.
FIGS. 7 to 12 show problems of bending loads in the plate combining
part of a wheel, and means of preventing bending according to the
present invention.
Sets of two plates each are combined with the rim and hub in the
form of an isosceles triangle, with the apex on the rim side, and
the base on the hub side. As shown in FIG. 7, parts 72 are
contacted with both surfaces of projection 35. The distance between
the plates on the hub side is larger, so that outward bends 81 are
made in the base parts of parts 72. Parts 72 are riveted by passing
rivets 94 through holes 79 and 38.
In such combination, when a lateral load F acts on the wheel, one
plate 70b will be subjected to a tensile force F.sub.1 but the
other plate 70a will be subjected to a compressive force F.sub.2.
The forces F.sub.1 and F.sub.2 will not act on the centers of the
fitting seat surfaces of the combining parts, but will act on bends
81. As a result, lateral load F will act as a bending load on such
parts to reduce lateral rigidity. This is the same also in the
fitting parts on the hub side. Thus, a bending load on such parts
results in plastic deformation of parts, unbalance of the wheel,
and instability in operation.
According to the invention, the center line of the plate is
intersected at the intersection of the plate combining part with
the axis of the rivet to increase the lateral rigidity and solve
such problems.
As shown in FIG. 8, fitting parts 85 having holes 79 are provided
on the right and left of the tip part of plate 70 by press-shaping,
and are shaped so as to form surfaces perpendicular to the axis of
the wheel, on both sides of projection 35. The area between fitting
parts 85 is not press shaped. The remainder of part 72, continued
linearly with the intermediate portion 86, is bent so that its
center line may substantially intersect the center line of hole
38.
When parts 72 are butted to both surfaces 37 and are combined with
the projection through rivets 94, the center lines N.sub.1 (FIG. 9)
in the lengthwise direction of plates 70 will intersect the center
lines N.sub.2 of the bolts 94 at their intersections with surfaces
37.
When a lateral load F acts on the wheel, one plate 70b will be
subjected to a tensile force F.sub.1, but the plate 70a will be
subjected to a compressive force F.sub.2. Forces F.sub.1 and
F.sub.2 will act on the intersections of the axes of the rivets 94
with the seat surfaces of parts 85, but will not act as bending
loads on plates 70a and 70b. Lateral load F will act only as
compressive and tensile forces on plates 70a and 70b.
The combining part on the rim side has been detailed in the above.
In the combining part on the hub side, the center lines of the
plates are intersected at the intersections of the axes of bolts 90
with hub fitting seat surfaces 57 so that the tensile force and
compressive force applied to the plates will not act as bending
forces, and thus a wheel having excellent lateral rigidity and
lateral load strength is obtained.
FIG. 10 is an explanatory view showing a method of reducing the
shearing stress of rivets in the case of combining plates with a
rim by rivets. When the joining surfaces of the plates with the
projection are vertical to the axle and to the axes of rivets 94,
the load on the wheel will act directly as a shearing force on the
rivets. To compensate for this, it would be necessary to make the
diameters of the rivets larger to increase the strength. Thus, it
will become necessary to enlarge the cross-sectional area of
projection 35, and the thickness of the plate. The weight of the
wheel will increase and the weight of the component part will
increase making the assembling work more difficult. In addition to
the above, in forming the plates to form an isosceles triangle the
opening angle with the apex on the rim side of the plates is an
important element in determining the rigidity of the wheel.
In consideration of the above, the invention is formed as in FIG.
10.
Projection 35 is formed to be wide in its base part and to be
narrow in the direction of the wheel center, forming symmetrical
tapered fitting seat surfaces 137. Parts 72 of plates 70 are bent
in their base parts to conform to surfaces 137. This bent tip part
72 is butted to surface 137, and rivet 94 is inserted through holes
38 and 79 to combine part 72 of each plate 70 with projection
35.
Rim 30 will be subjected to such compressive load in the vertical
direction as indicated by arrow F.sub.3. Because the cross-section
of projection 35 is a trapezoid, the load applied to this
projection will act as a vertical load on surface 137, and thus a
reduced force will act as a shearing force on rivet 94. Therefore,
the force acting on rivet 94 will be dispersed on the tapered seat
surface, and the shearing force applied to the rivet will be
greatly reduced.
Further, the opening angle of plates 70, which is an element
important to determine the rigidity of the wheel, can be made as
small as desired.
FIGS. 11 and 12 respectively show problems in the vertical load,
and a combining structure according to the invention in which they
are solved.
As shown in FIG. 11, parts 72 of plates 70 are contacted with both
sides of projection 35, and are riveted by inserting rivets 94 to
laterally pass through them. The load in the peripheral direction
when running will act on rivets 94. The stress will be concentrated
in the rivet and will act as a shearing force on the rivet. If it
is met with an increase of the diameter of the rivets, such
problems as described above will be produced. Further, as shown in
FIG. 11, both function and appearance may be impaired. The outer
end 74 of part 72 will become clogged with mud or the like, and
will be peeled outwardly due to minor flexing in the wheel and
minor movement of the joint.
As shown in FIG. 12, the outer end of part 72 is bent outwardly to
conform to the surface 34 of the inside diameter portion of rim 30
and to form a flange part 174. In combining part 72 with projection
35 by rivets 94, the outer end surface of part 174 is joined with
the inside diameter surface 34.
By the above, the load on rim 30 will act on the rivet combining
part and on part 174. The load in the vertical direction will be
transmitted to the combining part of the plate and the contact
surface of the flange part with the inside diameter of the rim, and
the stress concentration on rivet 94 will be reduced. Also, the
load in the peripheral direction will be reduced the same by the
surface contact of part 174, and the rigidity and strength of the
combining part of the plate with the projection, and that of the
entire wheel, will be improved. Due to the surface contacts of part
72 with the side of projection 35 and of part 174 with the inside
diameter portion surface of the rim, even when a surface pressure
is locally received by a rivet or the like, there will be no
deformation.
In the above, because the combining structure of an isosceles
triangle type is adopted, when a lateral load acts on the wheel,
one plate will be subjected to a tensile force, and the other plate
will be subjected to a compressive force. Because each plate is in
surface contact also in the vertical direction as mentioned above,
the load will be dispersed and local stress concentrations will be
prevented. Peeling and floating up of the tip of the plate will not
occur, the appearance will be good, and clogging of the combining
part with mud or the like will be prevented.
The tip part of the plate is bent substantially orthogonally in the
above illustrated embodiment, but it may be curved outwardly as
shown in FIG. 2.
In the foregoing embodiments, each plate 70 is combined in four
places; two places on the right and left sides of projection 35,
and two places on the stepped part 53 of hub 50. It is difficult to
keep the precision of alignment of holes 38 and 58 in the rim and
hub, and of 78 and 79 on the plate side good. If such precision is
kept good, the workability and assemblability is improved.
FIGS. 17 and 18 show structures in which the ease of fitting of the
fitting plates to a hub according to the invention is improved.
One hole, for example, hole A of holes A and B, which are the holes
78, separated from each other by a span L in the base end fitting
part 71, is formed to be precise in diameter as a positioning hole
so that its inside diameter may closely fit the outside diameter of
bolt 90. The other hole B is made a loosely fitting hole by
retaining a clearance between bolt 90 and hole B up to a
predetermined limit required for combinability and precision of the
product. The fitting holes 79, or C and D, on the right and left of
fitting part 72 in the tip part are formed to keep a span H in the
lengthwise direction with respect to holes A and B, and separated
from each other by a span L.sub.1 in the width direction. Holes C
and D are set to be of an inside diameter larger than the outside
diameter of rivets 94, and are made loosely fitting holes the same
as mentioned above.
The plate 70 is combined with the rim and hub as follows. As shown
in FIG. 18, first a bolt 90A is inserted through the positioning
hole A and is combined with the hub 50 side. Then a bolt 90B is
inserted through hole B. A clearance .DELTA.S will be generated
between bolt 90B and the inside diameter of hole B. Plate 70 is
pivotally moved with bolt 90A as a fulcrum within the range of
clearance .DELTA.S. As a result, the fitting part 72 will be
movable within the range of the angle .beta., will be able to
easily match holes 38 provided at the same span in projection 35,
and the rivets will be able to be easily inserted through the
fitting holes to rivet the plate.
Because the range of clearance .DELTA.S is set as above mentioned
and the tip part is made rotatable in the rotating direction, the
error in the radial direction, i.e., in the direction H, will be as
small as possible, the precision of the component parts will be
maintained, and assembly will be made easy and simple. When plate
70 is press-shaped and holes A, B, C and D are shaped, if only one
hole is made to maintain the precision and the other holes are made
loosely fitting, in fitting the plate to the rim and hub, the
positions of the fitting holes will be easily adjusted and
conformed while maintaining precision. Thus the assembly of the
plate and wheel is improved favorably to mass-production of
wheels.
A combining structure of the plates with the hub will be explained
with respect to FIGS. 19 to 22. Plates 70 are combined with hub 50
by providing the fitting holes in two places on the right and left
of part 71. There will be a gap between adjacent plates, and a span
between the adjacent bolts 90 through adjacent plates. Therefore,
strength and rigidity will be less than desired. If possible, it is
preferable to increase the strength and rigidity by setting the
span between the combining places, L, to be as long as possible.
Also, as each plate is fastened in two places on the hub side, the
number of the bolts will be double the number of the plates. This
is not advantageous to the weight. And, the fewer the fastening
places, the more advantageous the assembly.
The fitting parts 86 and 87, having the fitting holes 78 provided
on the right and left, at spaced-apart edge portions of part 71 are
expanded sidewise so that holes 78 may be formed on the boundaries
between the expanded fitting parts 86 and 87. In the illustration,
parts 86 and 87 are expanded to be semicircular. The fitting part
86 on one side is made a stepped fitting part stepped in the
direction of the outside surface of the plate, in the form of a
circle expanded from the sides of part 71. The amount of the step
of part 86 on the plate surface is a height W, equal to the
thickness of plate 70. Part 87, on the other side, is made flat so
that the stepwise expanded part of the fitting part 87 may overlap
the stepped part of part 86, and the overlapped back surface will
be flat.
In the combination of plates 70 with the hub, parts 87 and 86 of
one plate 701 and the other plate 702 are overlapped on each other,
the expanded part of part 87 fitting beneath the stepped part of
part 86 to align holes 78 with each other. Bolt 90 inserted through
hole 58 provided in stepped part 53 of hub 50 passes through holes
78 and is fastened with a nut. The other fitting part and the
opposed fitting part of the next adjacent plate will be in the same
relation. The overlapped fitting parts are combined with each other
by the bolt and nut. The base parts of the adjacent plates are
fastened with one bolt in common, and all the plates to be
assembled on the periphery of the hub are thus combined with the
bolts in common. The combined state is shown in FIGS. 22 and
23.
Because each plate is combined with the adjacent plate through one
bolt in common by overlapping the right and left end parts on the
hub fitting side of the respective plates as in the above, the span
L.sub.2 between the combining parts is longer. Because the plates
are not independently combined, the span between the combining
parts will not vary and the plates will be fitted to the hub with a
long and equal combining span.
Because the bolts on the hub side are used in common, the number of
the bolts will be half the number of the combining parts, so the
assembly work will be simplified, the weight of the wheel will be
reduced by the decrease of the component parts, and the cost of the
wheel will also be reduced. In this manner, as the base part of
each plate is fastened in two places at both ends, it will be
combined strongly and stably without impairing the strength of the
combining part, and the span between the combining parts, L.sub.2,
will be made as large as possible, and the strength and rigidity of
the wheel will be increased without using any additional
reinforcing member or modifying the structure of the wheel.
A preferred embodiment of the invention is explained in the
following.
The wheel according to the invention may be used specifically for
motorcycles. The damping of the oscillation when the wheel is
subjected to external disturbances from a road surface, which is an
important factor in the steering stability of a motorcycle, shall
be explained.
A road may be thought to be flat at a glance but, in fact, there
are various external disturbance factors on the road and the
motorcycle running on the road is always subjected to them. How
quickly the motorcycle absorbs such external disturbances is an
important factor.
When a motorcycle running at any speed is subjected to an external
disturbance, i.e., caused by shaking of the steering handle, the
convergence of the subsequent steering angle, i.e., the effective
angle of the steering handle, is graphed in FIG. 25. In the graph
in FIG. 25, the abscissa indicates time, and the ordinate indicates
the steering angle of the steering handle.
In order to evaluate the convergence, a logarithmic attentuation
rate d is determined as represented generally by the following
formula:
where
x.sub.1 is the size of the steering angle for a first time, and
x.sub.2 is the size of the steering angle for a second time.
This attenuation rate is influenced by the position of the center
of gravity, and the characteristics of the motorcycle, but the
element of the rigidity of the wheel is a major factor.
On the basis of various experiments, the rigidity coefficient f of
the wheel, influencing the attenuation rate, can be determined from
the following empirical formula: ##EQU1## where the respective
symbols are as follows:
n: Number of set of a pair of plates each.
A: Average cross-sectional area per plate.
.theta.: Opening angle of load acting lines.
l: Length of the plate.
K: Constant of the plate material, which is K=1 when the material
of the plate is an iron series, and K=0.61 when the material of the
plate is an aluminum series.
As a result of testing on various motorcycles, the relation between
the rigidity coefficient f and logarithmic attenuation rate d has
been established and, the characteristic shown in the graph in FIG.
26 has been determined.
As shown in the graph, when the rigidity coefficient f is above
0.026, the value of d will be comparatively constant, but when f is
below 0.026, the value of d will quickly decrease. When the value
of d is below 0.2, a very unstable state exists and, in the worst
case, the motorcycles will tumble.
The wheel according to the invention is formed to have a rigidity
coefficient above 0.026. The fundamental structure of the wheel
according to the invention is as already described, and
schematically shown in FIG. 24; the tip parts of a pair of plates
70 are riveted to the right and left side surfaces of projection 35
with rivets 94, and the base parts of plates 70 are fastened to hub
50 by bolts 90 to form, in the vertical cross-section through the
axle of the wheel, an isosceles triangle with the apex on the rim
side and the base on the hub side.
Therefore, in FIG. 24:
l: Length of plate 70.
t: Thickness of projection 35 of the inside diameter portion of the
rim.
.theta.: Opening angle of load acting lines, i.e., the plates
70.
b: Width, i.e., the width of the fitting part of hub 50.
As the length l of plate 70 is naturally determined by the kind of
vehicle, the number n of the sets of plates 70 and thickness of
plate 70 are selected on the basis of required strength. As it is
desirable to set the opening angle .theta. of the plates, which is
a factor in to the rigidity coefficient f, to be as large as
possible, the thickness t of projection 35 is selected as
follows.
Usually the width b of the axle part of hub 50 is limited due to
the space required for fitting the brake drum, brake disk, and
driving system, such as the sprocket, and is limited to be 90 mm.
at most.
Under such circumstances, as a result of experiments on the
relation of thickness t with the opening angle .theta. of plates
70, the maximum thickness t of projection 35, where the desired
rigidity coefficient f can be obtained, is 14 mm.
It is preferable that the thickness t of projection 35 be smaller,
but the minimum value is determined by the strength required of the
projection. The factor determining the strength is the impact force
in colliding with a vertical curbstone. If the rigidity of the rim
alone is considered, the minimum value of the thickness t will be 4
mm.
Therefore, the thickness t of projection 35 may be freely selected
between 4.ltoreq.t.ltoreq.14.
When the rigidity coefficient f of the above mentioned wheel is
made f>0.026, and the thickness t of projection 35 is made
4.ltoreq.t.ltoreq.14, a wheel of excellent rigidity and strength is
obtained.
By forming the invention as in the above, the rigidity, which is an
important element in the steering stability of the motorcycle can
be kept above the desired value, external disturbances received by
the wheel during running can be absorbed well, and the steering
stability can be positively retained.
Then, by setting the thickness of the projection of the rim as
mentioned above, even with the restricted width of the axle part of
the wheel, and required length of the plate, the rigidity of the
wheel can be kept above a predetermined value by selecting the
opening angle of the plates. Further, the pair of plates cooperate
with each other so that one plate is subjected to tension and the
other is subjected to compression, the stress is distributed, the
balance of forces on the right and left sides is kept even against
external disturbances given to the steering handle, and steering
stability is improved.
* * * * *